Dometic is a pretty smart company when it comes to t-stats. Even way back with the original 4 button, 5 button and now the 10 button t-stats, they always provided for us technicians the opportunity to trouble shoot and re-boot the t-stat to get it back to its original format state. Holding down the "mode & zone" buttons while turning on the main power button always tells you first if there is an issue and reloads the eeprom so it can recognize who and what is attached to it. Hope this helps, Fred